Line a baking sheet with parchment paper and set it aside. Measure out every ingredient before you start. This keeps the mixing fast and the dough easy to handle.
Add the peanut butter, honey, vanilla, and salt to a large bowl. Stir with a spatula until the mixture turns smooth and glossy. If your peanut butter is stiff, warm it for ten seconds first.
Pour in the oats, ground flaxseed, and chia seeds. Fold everything together until no dry patches remain. The dough will look thick and a little sticky, which is exactly right.
Add the mini chocolate chips and gently stir them through the dough. Make sure they are spread evenly so every bite has some chocolate. Save a few extra chips to press on top later if you like.
Cover the bowl and place it in the fridge for 30 minutes. This rest lets the oats soak up moisture and the dough firm up. Skipping this step makes rolling messy and sticky.
Scoop about one tablespoon of dough and roll it between your palms. Press firmly so the ball holds together and looks smooth. Place each one on the lined tray, leaving a small gap between them.
Pop the tray back in the fridge for 10 to 15 minutes to set the shape. Then transfer the balls to an airtight container. Enjoy them cold or let them sit for a few minutes for a softer bite